/* 这种注释编译后会出现在css上 */
#demo {
  color: blue;
  background-color: red;
  width: 200px;
  height: 150px;
}
#demo .word {
  line-height: 150px;
}
.second {
  background-color: green;
}
.class {
  width: 1;
}
.class .brass {
  height: 3;
}
